United overhauls MileagePlus rewards program with major changes

United Airlines is shaking up its MileagePlus rewards program in a move that benefits credit card holders and leaves other travelers earning fewer miles.

The Chicago-based carrier announced Thursday that starting April 2, travelers with United’s co-branded credit or debit cards will earn significantly more miles when they book flights. Meanwhile, customers without a United card will have a lower accrual rate.

Under the new structure, cardholders can earn up to twice as many miles per...